Propeller-dam



(No Model.) 2 SheetsSheet 1. G. CLARKE.

PROPELLBR, DAM.

No. 412.6 Patented Oct. 8, 1889.

N. PETERS. Phomlflhompher. wmingtun. 0.1:.

UNITED STATES PATENT UFFICE.

GEORGE CLARKE, OF JERSEY CITY, NEWV JERSEY.

PROPELLER-DAM.

SPECIFICATION forming part of Letters Patent No. 412,697, dated October 8, 1889.

Application filed May 14, 1389.

To all whom it may concern.-

Be it known that I, GEORGE CLARKE, a citizen of the United States, and a resident of Jersey City, New Jersey, have invented cer= tain Improvements in PropellerDams, of

which the following is a specification.

The object of my invention is to, construct a propellerdam for vessels of the twin-screw type, by which only the propeller to be re paired will be incased,and not the stern of the vessel, as in ordinary coffer damsof this class.

Referring to the drawings, Figure 1 is a sectional elevation of my improved propellerdam, showing its position in relation to the vessel. Fig. 2 is a section on the line 1 2, Fig. 1; and Fig. 3 is a section on the line 3 4, Fig. 1. Fig. 4 is a sectional view of the stern of the vessel with one of the dams attached. Fig. 5 is a view of the dam applied toa vessel of the single-screw type. I

A A are the heads of the dam, made, prdferably, of wood, and having stay-bars a a, of wood or iron, and connecting these two heads together is a body B, of the shape shown in Fig. 1. This body is also made, preferably, of wood or sheet-iron, and suitably stayed by angle-bars b b.

There is sufficient iron used in the construction of this propeller-dam to allow it to sink a certain depth in the water, so that it can be readily shipped in position around the propeller-shaft.

The head A is slotted, as shown in Fig. 1, and adapted to grooves c c. In this head is a gate 0. The lower portion of this gate is cut away for the reception of the bracket D of the propeller, and a portion of the headA is also cut away to receive this bracket D. On the top of the gate 0 is a bar F, through which pass bolts f, hung to the head A at f, Fig. 1, and adapted to these bolts are handled nuts f so that when the gate is placed in position the handled nuts are turned, making a tight fit between the gate and the head A. Suitable strips of packing may be placed around the gate to prevent water from gaining access after the propeller-dam has been- $erial No. 310,727. (No model.)

plate H, and on each side of the propellerdam are plates G, having orifices which cor respond with orifices in the plate H. Bolts are adapted to these orifices and nuts applied which will hold the propeller-dam in position with respect to the vessel, as the propellerdam is secured to the vessel as well as to the propeller bracket. To prevent the outer end of the propeller-dam from lifting, I place struts or shores from the dam to the under side of thevessel, as shown in Fig. 4. v

The propeller-dam is of a size sufficient to take in the blades e of the vessel, and is shifted in position, as shown by dotted lines in Figs.

1 and 4, after which it is turned up, as shown by full lines in Figs. 1 and 4, and secured to the vessel. After it has been pumped out, workmen can enter the dam and remove one or more blades of the propeller for repairs, and can gain access to any portion of the propeller, as circumstances require.

I have shown in the drawings the propeller having three blades; but any number of blades may be used, as circumstances may require.

.By making the propeller-dam in the shape shown it can be applied either to the right or left hand propeller without alteration, as shown in Fig. 4.

The opening in the head A is made sufficiently large in order to take in the propeller without enlarging the dam.

In Fig. 5 I have shown the propeller-dam adapted to a vessel of the single-screw type, the dam in this instance being placed in the screwspace between the rudder-post and the sternpost of the vessel.

' I claim as my invention- 1 1. The combination, with a propeller or coffer dam for vessels, of the heads AA, with the body B, the head A having an opening for the reception of the shank or bracket of the propeller and a gate for closing said opening, substantially as specified.

2. In combination, a propeller or coffer dam for vessels, having two heads, one of which is adapted to receive the shank or bracket of the propeller, said dam having a body of the form substantially as shown and described, so that the said propeller=dam will fit over either the right or left hand propeller, a bar F, secured to the head, with bolts pass substantially as described. ing through said bars, and nuts for forcing 3. The combination of the heads AA'and the the gate to its seat. body B, with securing-flange on the body, said In testimony whereof I have signed my name 5 flange being adapted to be secured toa flange to this specification in the presence of two I5 on the vessel, substantially as described. subscribing Witnesses.

4. The combination of the heads A A, the GEO. CLARKE. body B, an opening in the head A for the \Vitnesses: reception of the shank or bracket of the pro- WILLIAM D. CONNER, 1o peller, with a gate 0, adapted to said opening, HARRY SMITH. 

